1. Field of the Invention
The invention concerns a process for manufacturing a cement clinker in a plant as well as a cement clinker manufacturing plant as such.
2. Description of Related Art
Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
The manufacture of cement uses for its greatest part a baked matter, clinker, which is generated from minerals whose essential constituent is calcium carbonate. Clinker is prepared using a baking operation which produces large amounts of carbon dioxide, by the decomposition of calcium carbonate as well as the combustion of the fuel necessary to the operation.
For example, the production of a ton of so-called Portland cement thus emits approx. 530 kg CO2 from the treated matter and 250 to 300 kg CO2 from the fuel. This carbon dioxide is emitted in flue gases, at a concentration lower than 30%, wherein the principal component of the flue gases is nitrogen. Under these conditions, it is difficult to isolate, in particular to sequestrate for the purpose of limiting the discharges of CO2 into the atmosphere.
Manufacturing a cement clinker most often uses a so-called dry baking process, where the previously crushed raw matter is calcinated in a rotary furnace. So as to reduce the energy requirements of the operation, exchangers have been added upstream and downstream of the rotary furnace and directly recover the heat contained in the matter and the flue gases leaving the furnace.
A cyclone preheater is provided upstream where the raw matter is preheated in suspension, and partially decarbonated. A clinker cooler is provided downstream where the baked matter is cooled by cold-air blowing. Most plants operating in so-called dry mode comprise a combustion reactor at the bottom of the preheater, referred to as precalcinator, wherein a significant portion of the fuel consumed by the baking unit is provided, and in which the calcium carbonate contained in the matter in suspension performs a major portion of its decarbonation reaction.
The object of the present invention is to remedy the drawbacks aforementioned while offering an economically viable method for manufacturing a cement clinker for limiting the carbon dioxide discharges into the atmosphere.
Another aim of the invention is to provide such a process which can be implemented in a plant technically close to that normally used for the production of cement clinker.
Another aim of the invention is to provide such a plant.
Other aims and advantages of the present invention will appear in the following description which is given only by way of example and without being limited thereto.